Apparatus for conditioning loose porous materials



April 15, 1958 F. MAGNUSSQN APPARATUS FOR CONDITIONING LOOSE POROUS MATERIALS Filed Sept. 18. 1953 April 15, 1958 F. MAGNussoN APPARATUS FOR CONDITIONING LOOSE POROUS MATERIALS Filed Sept. 18, 1953 2 Sheets-Sheet 2 United States Patent APPARATUS FOR CONDITIONING LOOSE POROUS MATERIALS Folke Magnusson, Stockholm, Sweden, assignor to AB Svenska Flaktfabriken, Stockholm, Sweden Application September 18, 1953, Serial No. 381,105

3 Claims. (Cl. 34-179) The present invention relates to an improved method and an apparatus for conditioning, for instance, heating porous material preferably of the fibrous kind. More particularly, the invention relates to a novel method and apparatus for drying and conditioning water soluble cellulose derivatives which usually contain water and occluded air, that is, enclosed air entrapped by the fibres of the material.

When heating or otherwise conditioning a material in an apparatus in which the heat exchange is eflfected by contact between the heated or cooled surfaces and the material, the heat exchange must overcome resistances of two kinds, i.e. the outside resistance between the conditioning surface and the material and the inside resistance in the material proper. The second factor depends on the material to be treated. The treatment of porous, fibrous material, the heat conduction of which is very poor owing to the insulating eifect of the air occluded in same, will therefore take a lot of time and the treated material will be heterogeneous. The main object of the present invention is to eliminate these drawbacks.

The method according to the invention is characterized in that the material is periodically pressed against and then released from the conditioning surface.

A corresponding apparatus according to the invention is characterized by two tubular bodies, the wall surfaces of which are shaped as contact surfaces and effect the change of condition of the material, said wall surfaces being movable in such a manner that the material is periodically pressed against and released from the surfaces, respectively.

Other characteristics of the invention will appear from the claims and the following description of the figures.

Fig. 1 is a longitudinal section of an apparatus according to the invention, and

Fig. 2 is a cross section on line IIII of Fig. 1.

Referring to the form of apparatus shown in the drawings, the portions of the material to be treated are fed through the openings 13 of the apparatus and discharged into the space between the two cylinders 4, 6. The inside of the cylinder 4 in the embodiment illustrated is supported eccentrically in thebearings 9, 16 and the cylinder is rotatable in relation to the external cylinder 6 which in turn either can be stationary in a mounting 1 or can be rotatable in a suitable support not shown in the drawing as being no part of this invention. The rotation can take place in the clockwise direction or alternatively in the counter clockwise direction in relation to the inner cylinder. In case the conditioning of the material involves heating or cooling a suitable heating or cooling liquid is supplied through the tube 17 and the airtight packing box 20 into the cylinder 4 or to a number of separate heating or cooling elements arranged in the jacket of the cylinder. In a corresponding manner the liquid is carried off through the packing box 10 and the tube 8.

The jacket of the external cylinder can also be pro- 2,830,386 Patented Apr. '15, 1958 vided with similar arrangements for effecting changes in the condition of the fed material to be treated between the cylinders. The driving means of the inner cylinder consists of two gear wheels 15, 21 which are driven, for instance by an electric motor 22. The external cylinder is provided with the lower openings 24, 25 through which the conditioned material is carried off. The reference numerals 3 and 7 (see Figs. 1 and 2) designate an arrangement for emptying condensate which is collected on the bottom of the cylinder and this action takes place one time during every revolution of the apparatus.

The device functions as follows. After feeding a portion of the material through the upper openings 13, 13, said openings are closed by means of doors and the driving motor 22 is started to thereby rotationally drive at least the inner cylinder. By this operation, the material successively pressed wedge-shapedly between the surfaces of the two cylinders causing the change of condition and then is released from between said surfaces. The material will thereby periodically expand thus causing a considerable changing of the position of the particles in relation to each other. This provides a resting period for the particles as during this expanding they will be insulated from each other. This form of treatment is very important to cellulose derivatives and similar fibrous materials. To obtain the best result from a qualitative view point by conditioning such materials it is important that the inner diffusion is not forced.

According to the illustrated embodiment of the invention the inner cylinder is provided with separate members 5, 11, 19 in order to facilitate the movement of the material or increase the contact surfaces actuating the material. The members 5, 19 consist of radial bars mounted on the gable-end walls of the cylinder in order to prevent the material from accumulating or agglomerating there. Without such members the cylinder 4 would be subject to an increased friction resistance owing to the material adhering on the two gable-end walls. According to another embodiment it is convenient to arrange the external cylinder as a completely closed pressure chamber and/or a vacuum chamber when treating materials according to the above mentioned method.

Although the arrangement described above relates to drying in batches it is, however, possible to provide the ends of the external cylinder with openings for continuously feeding or emptying of the apparatus. Other modifications of the apparatus are also possible within the scope of the claims.

What I claim is:

1. Apparatus for conditioning loose porous materials, preferably of the fibrous kind, by heat exchange therewith elfected by direct contact of the material with a heat exchange surface, comprising an outer cylindrical drum, an inner cylindrical drum mounted within the outer drum eccentrically thereof, means to control the temperature of at least one of said drums for direct heat exchange with the particles of the material, and means to rotationally drive at least one of said drums to effect relative movement therebetween and cause the material to be advanced and successively compressed between the surfaces of the drums and then released therefrom for rearrangement of the particles of the material.

2. Apparatus as claimed in claim 1 wherein one of the drums is stationary and constitutes a closed chamber designed to Withstand substantial positive and negative pressures.

3. Apparatus as claimed in claim 1 wherein the external surface of at least one of the drums is provided with fins to elevate the material and increase the active contact surface thereof.

(References on following page) References Cited in the file of this patent 791,877 Caspar June 6, 1905 UNITED STATES PATENTS 2 ---7 i 487,912 camera a1. Dec. 13,1892 2j6O0j843 fiif fi :31 1952 536,336 Gubbins Mar-26,1895 5 2,647,851 Schwartz Aug. 4, 1953 697,312 Atwood Apr. 8, 1902 

